/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.jena.atlas.lib;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.List;
import java.util.Properties;

/** Sorted output */
public class PropertiesSorted extends Properties {
    private Comparator<String> comparator = null;

    // public SortedProperties() { super() ; }

    public PropertiesSorted(Comparator<String> comparator) {
        super();
        this.comparator = comparator;
    }

    @SuppressWarnings({"unchecked", "rawtypes"})
    @Override
    public synchronized Enumeration<Object> keys() {
        // Old world - enumeration.
        Enumeration<Object> keys = super.keys();
        List<String> keys2 = new ArrayList<>(super.size());

        for ( ; keys.hasMoreElements() ; ) {
            Object obj = keys.nextElement();
            if ( obj instanceof String str )
                keys2.add(str);
        }
        // Keys are comparable because they are strings.
        if ( comparator == null )
            Collections.sort(keys2);
        else
            Collections.sort(keys2, comparator);

        return new IteratorToEnumeration(keys2.listIterator());
    }

    static class IteratorToEnumeration<T> implements Enumeration<T> {
        private Iterator<T> iterator;

        public IteratorToEnumeration(Iterator<T> iterator) {
            this.iterator = iterator;
        }

        @Override
        public boolean hasMoreElements() {
            return iterator.hasNext();
        }

        @Override
        public T nextElement() {
            return iterator.next();
        }
    }
}
